The investigation of the process of ribosome assembly in the oocytes of Xenopus laevis is continuing. We have found that we can induce an increased rate of amino acid uptake, an increased rate of protein synthesis and an increased rate of ribosome assembly in isolated oocytes in culture using human chorionic gonadotropin at the proper concentrations. We have also found that oocytes from non-hormone stimulated females accumulate intermediates in the ribosome assembly process. Using our in vitro hormonal treatment we are investigating the assembly steps which appear to be stimulated by the gonadotropin. Our other work is a continuing study of the quantitative and qualitative aspects of mitochondrial DNA accumulation in the developing oocytes of X. laevis.